Process for the conversion of liquid substances into finely divided form



Dec. 15, 1942. LANDGRAF 2,305,172

PROCESS FOR THE CONVERSION OF LIQUID SUBSTANCES" INTOA FINELY DIVIDED FORM Filed May 12, 1939 2 Sheets-Sheet 1 l1 /XJZ 0520 la/rzdyrdf,

Decks; 1942. o. LANDGRAF 2,305,172

PROCESS FOR THE CONVERSION OF-LIQUID SUBSTANCES INTO A FINELY DIVIDED FORM Filed May 12, 1939 2 Sheets-Sheet 2 Fig. 6

Ofio Landraj the next beating element.

Patented Dec. 15, 1942 UNITED. TATES. PATENT OFFICE azors-:2

LIQUID DIVIDED FORM SUBSTANCES INTO FINELY Otto Landgraf, Frankfort-on-the-Main, Germany, assignor, by mesne assignments, to Chemical Marketing Company Inc., New

York, N. Y.

Application May 12, 1 In Germany 939, Serial No. 273,330

May 5, 1938 mm. ('01. 83-91) I example, a rapidly rotating disc, thereby subjecting it to the action of centrifugal force and subject it simultaneously to a beating action transversely to the direction of impact with them-- tating element, and causing a stream of cooling liquid to impinge upon the rotating element simultaneously with such molten metal, thequantity of the cooling liquid being sufiicient that it is sprayed off the rotating element simultaneously with the finely divided metal. Because of the difi'erent forces acting on the molten metal to be comminuted, such as the impact of the molten metal upon the rotating element, centrifugal action and beating action, extraordinary efiects, for example, with respect to the degree of fineness of the resulting comminuted product, may be obtained with large outputs.

For carrying out the process in accordance. with the present invention rotating elements may be employed which are provided with inequalities, such as elevations ordepressions, so'that' the molten metals supplied to the elements are subjected to the desired beating action. Discs provided with beating elements such as fillets, ribs or channels, which may, for example, proceed in a radial direction or obliquely thereto, may be employed in accordance with the-inven tion. The fillets and the like may be straight or be constructed as blades in order to throw the impinging mass and resulting particlesin a cer-.

In the disposition and construction of the beat ing elements care must be taken that the particles are centrifuged on the rotating element and do not collect and adhere to the beating elements. v V

According to one embodiment of the invention, the rotating elements are provided with openings, the edges of which exert a vigorous beating action upon the molten mass and resulting particles which enter such openings. Advantageously the rotating elements are provided with 1 beating blades and openings. w

posed so-close together that the expanding molten .metal or the particles resulting therefrom are in I struck by such beating arms,

' drawings.

Fig. 1 shows a plan viewof a disc-like rotating element I, which is provided with radially dis- I posed fillets 2.

A plan'view of a rotating element illustrated in Fig. 1 is. shown in Fig. 2, the fillets 3 of which,

ally. The fillets may bev disposed at any distance apart, the actual distance between each fillet depending on'the speed of rotation of the rotating element.

-. Two further arrangements of the fillets are right side of' the rotating element fillets, ribs or the'like which are interrupted are illustrated,

to one another so that the mass of particles",

which have passed an interruption is caught by The surface of the rotating elements may be provided with different kinds of beatinglele ments, such as teeth, knifeedges and the like, so that the particles upon their passage from the, center of the rotating element to the periphery fillets are illustrated in Fig. 4.

.further slightly displaced ribs or the like being disposed at the interruptions so that the mass of particles passing through the interruptions is caught by the rib or fillet disposed behind the same. The left side of the rotating element are of blade-like construction.

.Several cross sectional shapes of the ribs or The fillets are preferably provided with a sharp edge so that -may be rectangular, trapezoidal or arched.

thereof are thrown from one beating-element against another and from the latter against another, and so on, until they are finally centri-- fuged off in a finely divided state.

' Fig. 5'shows another embodiment of a rotating element in cross section, the upper surface of which is provided with teeth, each of which is triangular in cross section.

necessarily be struck by the walls of the openings so that it is subjected to a lateral impact. Elevations I3 may also be provided on the rotating element next to these openings.

Fig. 8 is a side elevation of an apparatus for carrying out the present invention with a part of the casing broken away. In this fi ure, l4

'- represents the casing which serves to collect the material being comminuted. Tubes l5 and I6 respectively represent means for feeding the molten metal to be comminuted and the cooling liquid to the rotating element H which is provided with the beating elements I8.

when carrying out the process in accordance with the present invention with the aid of apparatus of the type hereinbefore described, it is essential to ensure that the particles do not be come. fixed upon the rotating element. It has been found that'sllch disadvantage may b ove come in an'excellent manner by causing a liquid, such as water, alcohol or the like, to impinge upon '-the disc simultaneously with. the molten'metals to be comminut'ed. These liquids to a certain extentact as fraction eliminators or lubricants and prevent any particles from adhering to and forming-agglomerations-on the rotating element. Consequently, in carrying :outthe process in action obtained 1'; also favorably influenced bythe I explosive evaporation of the liquids supplied to the rotating element.

The process in accordance with the present invention is carried out, for example, by causing a molten metal, such as fused silver-copper alloy, to impinge in a thin stream upon the rapidly rotating disc which is disposed in a closed chamber while simultaneously spraying cooling water on the The molten metal impinging on the disc is torn into extremely fine particles by the centrifugal forces. The comminution obtained may be extensively regulated by regulation of the thickness of the stream of molten metal supplied, the viscosity of the molten metal and the force of the impact of the molten metal upon the rotating element. By spraying cooling water on the rotating element simultaneously with the molten metal, the comminution obtained is promoted and-the disc and the particles obtained easily, for example, by roasting, dissolving out the copper with sulfuric acid and working up the silver, whereby silver of a high degree of purity is obtained.

. When ,comminuting alloys of the type mentione'dabove, the process may, for example, be

regulated so that the product, obtained is of such a grain size that it passes substantially oomcordance with the present invention, astream of molten metal is caused to impinge against the rotating disc and simultaneously therewith a duid, for example; water, is sprayed on the rotat ing disc and is sprayed oi! together with th metal particles produced.

- In carrying out the process in accordance with the present invention, it has further proved to be essential to provide for .the rapid cooling of vthe particles produced. This, it is found, prevents; the grains formed from coarsening by reassembly'ofthe fine particles and the formation of agglomerationswhich might occuron-the wallsof the comminutingchamber.

It was found that the liquids employed-as fric pletely through a sieve having at least 50 meshes per cm I claim:

A process fo v the conversion of molten substances into finely divided form, comprising causing said molten metals to impinge on a rapidly rotating surface to subject said substances to the action of centrifugal force, simultaneously subjecting said metals to a beating action by causing the metals under the action of said cent trifugal force to contact with elements disposed finely divided metal.

transversely to their normal path of movement under 'saidpforce and causing a stream of cooling liquid to impinge upon the rotating surface simultaneously withsuch molten metals, the

quantity of .said liquid being sufflcient that it is sprayed off the surface simultaneously with the O'I'IO LANDGRAF. 

